A single high polymer fuel cell is a fuel cell stack that includes a plurality of cells being mutually stacked to output a higher output. Each cell (smallest unit) includes a membrane electrode assembly (MEA), which includes an electrolyte film made of a proton exchange membrane and sandwiched between two electrodes, i.e., a fuel electrode and an air electrode. The cell, unit further includes two separators that sandwich the membrane electrode assembly.
The single high polymer fuel cell can generate electric power, as is conventionally known and is simply described below. A hydrogen containing gas, serving as fuel gas, is supplied to the fuel electrode (i.e., an anode-side electrode). An oxygen containing gas or air, serving as oxidizing agent gas, is supplied to the air electrode (i.e., a cathode-side electrode). The hydrogen containing gas, when it is supplied via a fuel gas passage to the anode-side electrode, is decomposed into electrons and hydrogen ions by a function of a catalyst layer of the electrode. Electrons move to the cathode-side electrode via an external circuit. On the other hand, hydrogen ions pass through the electrolyte film and reach the cathode electrode, where the hydrogen ions join with the oxygen and the electrons having reached via the external circuit, thereby generating reaction water. The heat generated by a binding reaction between hydrogen, oxygen, and electrons is absorbed by cooling water. Further, water generated on the cathode electrode (hereinafter, referred to as “generated water”) is drained from the cathode side.
The anode electrode and the cathode electrode of the above-described fuel cell are constituted by catalyst layers, respectively. The catalyst layer includes a plurality of gas diffusion layers laminated to diffuse the hydrogen containing gas or the oxidizing agent gas. However, if the drainage of the generated water resulting from the above-described reaction on the cathode side is not smooth, a blocking phenomenon (“flooding phenomenon”) may occur in the cathode electrode. Hence, the gas diffusion layer is configured to include a water repellent layer in addition to a layer that contains carbon fibers. The water repellent layer can expedite the drainage of generated water.
However, in a state where at least a part of carbon fibers in the gas diffusion layer protrudes from the layer surface, if the gas diffusion layer is laminated on the membrane electrode assembly, the membrane electrode assembly may be damaged by a protruded carbon fiber. Accordingly, it is necessary to prevent the membrane electrode assembly from being damaged by protrusion of carbon fibers.
A method discussed in the following Patent Literature 1 includes placing a gas diffusion layer substrate including fibers on a roller, bending the substrate along the roller, and integrating the substrate with a membrane electrode assembly after removing the protruded part of the fibers in a state where the protruded fibers are raised.
Prior Art Reference
Patent Literature
Patent Literature 1: JP 2008-198526 A